The background of the invention will be set forth in three parts.
1. Field of the Invention
The present invention relates to a revolutionary shape of a sport racquet or hammer handle that improves control of the movement of such racquet or hammer head. More particularly, the present invention relates to an accessory that can be used in all the competitive racquet sport's racquets such as tennis, racquetball, squash, and badminton racquets. This accessory also has other non-racquet handle applications, such as, in the golf stick, polo stick, and even in the ordinary construction hammer.
2. Technological Facts about Tennis
As the competition in racquet sports increases, new racquet designs have been developed to increase the power, control, and maneuverability of such racquets.
In theory, racquet design is fundamentally based on the need to increase two things: a) the power imparted to the ball and b) the control over the ball as it contacts the racquet head.
Power in tennis is a function of the force transferred from a player's body to the ball with the use of the tennis racquet. Therefore, a powerful racquet is such racquet that permits players of lesser strength to hit comparable shots.
Power without control is known to give players no extra benefit in the competitive arena. However, control over a shot depends on the spin imparted to the ball at the point when power is implemented. For this reason, new technology has always improved the power of such frames first and then improved the control of such new power. This game has been a race between the technology of power against the technology of control.
The ability to impart control (spin) to the ball depends also on different physical characteristics of the racquet such as: string thickness, string tension, balance of the racquet weight, flexibility of the frame, amount of frame vibration and grip quality.
It is known that all these physical characteristics of the racquet affect the player's ability to impart a rotational torque (spin) on the ball. The other obvious factor which is essential to a player's control is his body movement technique. These body movements include footwork, body position and shoulder, elbow, hand, and wrist movements.
Therefore, since the entire body movement technique is for the sole purpose of controlling the racquet head, and the physical characteristics of the racquet are so important; we can say that the link (grip) between the racquet and the hand of the player is perhaps the most essential in the manipulation of the racquet head. It is in this link or joint that we have an accessory that will benefit millions of players of all ages and levels.
3. Description of the Prior Art
U.S. Pat. Nos. 4,213,609 (Swanson) 3,905,598 (Ballog), and 3,817,521 (Wright) add a structure above the hand on the racquet shaft. These patents do not allow the player to lock his hand to the shaft. We know that as a racquet is swung in an arc, the centrifugal force acting on the racquet urges the racquet away from the player and the player's grasp. We also know that perspiration on the grip reduces the coefficient of friction between the racquet grip and the player's hand. In fact, the player must grip the racquet shaft even more tightly to prevent the racquet from flying out of this hand. We conclude from our experiments that the problem of slippage was not solved by the above patents.
Some new developments have focused on the racquet handle as the link between the racquet head and the muscle and sinew of a player's arm and hand. However, only the so called "hightech" synthetic grips and "overwraps" have improved the racquet handles of today's new high tech racquets. "Overwraps" seek to overcome problems caused by perspiration of the player's hand. "Hightech" synthetic grips overcome three problems; the uncomfortable sensation of a wet grip due to perspiration, substantial friction reduction and some shock absorbtion.
The problem of perspiration has been addressed and successful developments attained in the construction of new grip materials which replace the customary leather grips. These synthetic grip materials do not absorb moisture and do not become as slick as traditional leather grips. In addition, slightly flared racquet end caps or butt caps have been utilized for many years to close the end of the racquet handle and to reduce the possibility that the racquet might slip from the player's grasp.
Other attempts of improving the racquet handle such as in U.S. Pat. Nos. 3,817,521, (Wright); 3,905,598 (Ballog); 4,033,583 (Ehrhart); 4,213,609 (Swanson); 4,226,418 (Balfour), and Des. 289,671 (Abel) for example have not been proven successful in overcoming the problems mentioned above.
Other patents that have shown development of the conventional handle are: 4,072,312 (kahn), and 3,501,148, (Cheris, Bigos, and Mox) which emphasize the importance of the octagonal shape shaft.
The octagonal shape shaft and butt cap have been used for many years. The basic reasoning behind the importance of the octagonal shape is the following: since the baseline to baseline length of a tennis court is 78 feet, the angle that the ball is initially projected is critical to the path of the ball over the length of a tennis court. For example, a one degree change in the angle of force will result in a one and one half foot elevation change in the flight of the ball over the length of a tennis court. A slight variation in the angle of the racquet head will determine whether the ball lands within the boundaries of the court or if the ball lands out of play. The only way a player can feel the position of the head of the racquet, without looking at it, is by feeling the bevels of the octagonal shaft. Since the octagonal shaft has a side parallel to the face of the racquet, the player can determine the position of such face by mere tact.
The octagonal shape shaft is therefore useful. However, the sides of such polygonal shaft and butt cap continue to cause friction to the hands of the players.
The optimal grip would be such handle that would give us orientation of the head, shock absorbtion, minimal friction, and repel perspiration without causing perspiration.
Recent developments in racquet handles are described on pages 146 and 147 of the September, 1989 issue of Tennis Magazine. The importance of the racquet grip to the control of the racquet head is described in an article entitled "Handle Systems, Get a Grip!" In an illustration entitled "Shapes of the Future" on page 147, the hourglass and ribbed overwrap concepts are described. In the hourglass concept, the player grips the most narrow, tapered portion of a racquet handle. In the ribbed overwrap concept, the traditionally shaped rib to reduce slippage of the hand relative to the racquet handle is also described. Neither of these concepts have become widely accepted since the hourglass grip cannot be used by players who grip the racquet handle with both hands and because the hourglass slope does not fit the natural contour of a player's hand.
Although the ribbed overwrap concept is likely to reduce slippage of the player's hand relative to the racquet handle, the increased friction does not permit fine finger control over the racquet by players who adjust their hand and finger position during the operation of the racquet.
It is apparent that all known racquet handles do not overcome all the problems set forth above. Accordingly, a need exists for a racquet handle which permits a person to control racquet head movement without slippage of the handle, a handle that absorbs shock and a handle which reduces friction without losing sensory perception of the position of the head of the racquet.